'use strict';

function average_to_letter(collection) {

  //在这里写入代码
  let sum = 0;
  for(let i=0;i<collection.length;i++){
    sum += collection[i];

  }

  let ave =sum/collection.length;
  var m = String.fromCharCode(97+ave)
  return m;

}
module.exports = average_to_letter;

